New Features

The pg_loose_count extension now adds Database#loose_counts, which takes a schema name, and returns a hash of loose counts for all tables in the schema:
```
DB.loose_counts(:schema) # => {table: 123456, ...}
```
Database#create_table on PostgreSQL now supports a like method to copy schema information from another table. It supports including and excluding keyword arguments for the related clauses supported by PostgreSQL:
```
DB.create_table(:table) do
  like :other_table, including: :all
end
```
Database#alter_table on PostgreSQL 10+ now supports attach_partition and detach_partition methods, for attaching and detaching partitions.

attach_partition requires a block that uses the table partitioning DSL (the same DSL used for create_table with the :partition_of option):
```
DB.alter_table(:table) do
  attach_partition(:part) do
    from 3
    to 4
  end
end
```
detach_partition supports a concurrently keyword argument:
```
DB.alter_table(:table) do
  detach_partition(:part, concurrently: true)
end
```
If you were previously using create_table with :partition_of, you may want to consider combining create_table like with alter_table attach_partition, as it reduces the amount of locking required to add a partition to a table.
The SEQUEL_NAMED_TIMEZONES_USE_TIME environment variable is now respected by the named_timezones extension. If set, the named_timezones will not set datetime_class to DateTime. Starting in Sequel 6, this will be the default behavior.

Other Improvements

Sequel no longer uses alias inside a module to alias methods defined in Object. Instead, it uses define_method with Kernel.instance_method. This prevents warnings in verbose mode when running on Ruby 4.1.

Support for these features will be removed in Sequel 6.

Sequel.split_symbols= is now deprecated. Sequel disabled splitting symbols by default in Sequel 5. If your application still relies on symbol splitting, you can use github.com/jeremyevans/sequel-unsplit to handle the majority of the conversion. Related to this, the Sequel::SPLIT_SYMBOL_CACHE constant is now also deprecated
Sequel.datetime_class= is now deprecated. Sequel defaults to Time, and only supported setting this to DateTime. DateTime has been deprecated since Ruby 3.0. Most of the reasons to use DateTime went away in Ruby 1.9, and the last reason (timezone support) went away in Ruby 2.6.
Sequel.convert_two_digit_years= is now deprecated. Sequel has defaulted to converting two digit years in dates and timestamps since version 2.5.0 (over 18 years ago).
String#to_datetime in the string_date_time extension is now deprecated.
Sequel’s Microsoft Access support is now deprecated. The support never worked well enough to pass Sequel’s integration test suite.

Sequel now raises if attempting to quote an identifier containing ] on Microsoft access, and when attempting to quote an identifier containing “ on Oracle. The documentation already warned against using such identifiers, but since using them can result in SQL injections, it is better to raise instead.